The present invention relates to a fluid-operated supporting arrangement for a travelling mechanism having a plurality of wheels or wheel sets. It also generally relates to a safety device for pairs of any conduits.
Arrangements and devices of the above mentioned general type are known in the art. In a known pneumatic or hydraulic supporting arrangement there are a plurality of pneumatic or hydraulic supporting elements, such as cylinder-and-piston units, which support individual wheels or wheel sets and are connected in groups with one another and/or with a pneumatic or hydraulic accumulator via pairs of conduits which are provided near the supporting element or the accumulator with conduit breakage safety devices reacting to breakage of conduits. In conventional constructions, when one conduit of a pair of broken, the operational ability of the hydraulic or pneumatic mechanism, particularly the travelling mechanism, is maintained by the conduit breakage safety device, inasmuch as the broken conduit is blocked for preventing further losses of pneumatic or hydraulic medium. The remaining, unbroken conduit is sufficient in some cases for the operation of the arrangement. One such conduit breakage safety device for hydraulic travelling mechanisms is disclosed, for example, in German Pat. No. 2,319,611. In this device, two hydraulic cylinders are connected with one another by two separate, parallel-arranged conduits which communicate with the cylinders with interposition of a three-way valve. One passage of the three-way valve leads to the associated cylinder, whereas the two other passages lead to the conduits connected in parallel. The safety valve includes a common closing member for both conduit passages, which in its intermediate position opens both conduit passages and, during breakage of one conduit, displaces under the action of the thus produced flow pulse for blocking the passage leading to the not-tight conduit. In this safety device, the valve-closing member displaces when the flow to one conduit passage is stronger than that to the other conduit passage. Thereby, the displacement of the closing member increases the resistance of the flow to one conduit passage, and reduces the resistance of the flow to the other conduit passage. As a result of this, vibrations which take place during the travel and insignificantly different flow forces to both conduit passages can be increased, and therefore undesirable chatter vibrations of the connecting parts can take place. This reduces the operational safety of the conduit breakage safety device.